Ok, First let me start off by saying that I never would have spent my own money on any air intake for this car. My girlfriend decided to surprise me with the AFE Stage 2 Intake system and while I was grateful, I wasn't really too excited on putting this on my car. I do however mod every car I have ever owned and I didn't want to piss her off, so I installed the intake to please her and not make her think I didn't like it.
Installation:
The Installation went rather smooth for me considering the instructions they provide is total crap!!! The intake is actually from a 06+ 328i, but there isn't much difference between the 128i and the 328i. I will say though that if you are considering this intake system, make sure you buy the correct one. There are 2 variations, 1 with active power steering and one without. This will most certainly cause issues , so pay attention to which power steering you have and order accordingly. I'm thinking this may be the fitting issue another forum member had when installing his system. The only problem I ran into was the pipe that connects to the heat shield box has this shitty, flimsy foam gasket that is practically worthless, but still I managed to install the system within 40min.
Sound:
I know this is the main reason why everyone wants to put aftermarket intakes on their cars. While it does sound cool, I guess I'm getting older and can do without the added noise and attention, but however it does sound pretty cool. The damn thing gets pretty loud around 3.5K with resonating, deep/smooth moan all the way up to 6.5K RPM's. Most other Intake systems I've heard had a throaty tone to it, not this Intake system. I can see why some people have complained about drone ( Didn't know drone was possible with a Intake), but it's merely the deep, resonance sound the system makes if the RPM's are held around a constant 4K RPM range. This can only be a problem if you deliberately hold the RPM's at this range, so it's really not a major issue. On a scale of 1-10, I give the sound around a 7 since I didn't mind the sound of the stock N52 to begin with. Some will love it though I'm sure.
Appearance and Build Quality:
This system actually is built quite well and looks decent under the hood. The only problem I have is with the Aluminum heatshield, which I think would look better in a textured black finish, so I went to the local autoparts store and picked up some stuff to prep and paint the shield to my personal liking. (Picture posted below). I also like the fact that the heat shield is bolted up to one of the stock bolt holes that the stock air box was connected to which in turn makes the system stable. This is a + since the Injen system apparently just hangs there. I give the overall appearance an 8 out of 10.
Performance:
I will be the first to say that I never have seen or felt any gains from any air intake system aside from the turbo'd cars I have had in the past and my Twin Turbo'd 370z. I'm the type that is not susceptible about any basic N/A bolt-on gains on any car and it would really have to make some noticeable gains for me to believe otherwise. I mean, I have a car that I DRIVE ON THE WEEKENDS THAT MAKES JUST OVER 500WHP!! Not trying to brag, but I know when there is a gain and when there is not. Now, I have had the BMS PowerBox set on map 3 for over 4 month's and I never actually felt any benefit from this mod alone, but since I installed this Intake, the car has some extra pull up top!! The extra power kicks in around 3.5k RPM and I mean it actually kinda kicks you back in your seat a bit lol and seems to have the extra pull all the way to 6K. I was really surprised by this and so was everyone else that has taken a ride in my car. The "kick" could be from the ECU learning the new airflow or it could be because the the Intake and BMS PowerBox likes each other, I dunno, but since this is my daily driver, I will enjoy my ride from work and back a little more now.
The intake pipe also seems a lot cooler to the touch after driving around for a bit compared to stock, a big +. I give the performance aspect a 8 out of 10 and will update once the Intake has around 300+ miles on it for any changes I experience.
Final Impressions:
If you have your heart set on a Intake system on this car and have money to blow, I say go for it regardless of what anyone says. I was one of those guys that would try and deter other members from buying anything performance oriented for the 128i, but this car has surprised me so far and that is very hard to do. Sorry for the long post, but this Intake impressed me enough to waste the time and like I said, that's very hard to do considering past cars I have owned and the current weekend car I have now. Thanks for looking!!
Here's a quick picture with the painted heat shield cover: